Figure 57. Puhler sounder, described by Christian Puhler in 1563, repeated an idea first put forth by Cardinal Nicholas Pusanus a century earlier. The principle, was to attach a float to a weight making it heavier than water. Upon striking bottom, the float would detach. Depth would be derived from round- trip travel time. It is unknown if this device was ever field tested.
Photo Category: Oceanography - Historical instruments